All of the cross-referenced applications and publications contain control systems for internal combustion engines in which microprocessors are used. Further, hard wired computers are known, for example as described in U.S. Pat. No. 4,063,539. Such hard wired computers, of course, are not nearly as versatile as microprocessor systems. In the known microprocessor systems, very complicated programs for processing externally applied signals indicative of then-present operating parameters, for example, are required. These complicated programs in turn require a large amount of storage and, in particular, a large amount of fixed storage such as in a ROM. Further, if less than eight bits, for example, are used in the program, a decrease in accuracy at high engine speeds results.
In U.S. application Ser. No. 916,827 filed June 9, 1978 now U.S. Pat. No. 4,204,256 and assigned to the same assignee, an inputoutput unit is described in which a number of mathematical operations are carried out which obviate some of the abovementioned problems. However, the particular problem of determining the injection and/or ignition timing as a function of the quantity of air in the inlet pipe of the engine is not addressed.